A recurring translocation (X;20)(q13;q13) was found in four women ranging in age from 57 to 77 years. They had myelodysplasia, myelodysplasia with thrombocytopenia and pancytopenia, transforming to myelofibrosis, and myelodysplasia with sideroblastic anemia, respectively. The t(X;20) was the sole abnormality in three cases; one case also had a der(1;7)(q10;p10). Added to three previously reported cases, our four cases bring the total to seven; thus, t(X;20)(q13;q13) is a nonrandom translocation associated with myeloid disorders. Previous FISH studies showed that the breakpoint on the X is proximal to XIST. In one of our cases, the breakpoint on the X was shown to be proximal to Xq12, by FISH using a probe for the androgen receptor gene locus.